Electrode release for arc lamps



Oct. 3, 1939.

F. c. COATES 2,174,736 ELECTRODE RELEASE FOR ARC LAMPS Filed Aug. 27, 1938 3 Sheets-Sheet 1 1 22621 71 INVENT OR.

E 3, flaw/v6 C 60,4755,

Oct. 3, 1939, F. c. COATES 2,174,736

ELECTRODE RELEASE FOR ARC LAMPS Filed Aug. 27, 1958 3 Sheets-Sheet? E, 119 92 4- f 107 105 v m 111 109 ff 5 a 1 I I I 110 f 5 In: 1 1 k w 112 25 s I 113 46 1 11a 28 W if 52 l .63 3g 1J7 .27 A

INVENT OR.

ATTORNE Oct. 3, 1939. VF. c. COATES ELECTRODE RELEASE FOR ARC LAMPS Filed Aug. 27, 1938 3 Sheets-Sheet 3 I NVENTOR. flaw/v6 CI C04 755,

l f/ w ATT Patented Oct. 3, 1939 UNITED STATES 2,174,336 ELECTRODE RELEASE FOR Aiw LAMPS Fielding 0. Costa, Los Angeles,

Calif., assignor tuition-Richardson 60., Los Angeles, Calif., a limited partnership of California Application August 27, 1938, No, 227,142

12 Claims. (Cl. 176-119) w invention relates to an improved electrode release for are lamps and has particular utility when employed with arc lamps of the type in which the electrode is continuously rotated and advanced during operation.

In arc lamps of the type for which the subject matter of this invention is adapted for use, either one or both electrodes are continuously rotated during the operation of the lamp. An example of this type of arc lamp is disclosed in the United States patent to Elmer 0. Richardson, No. 2,060,347.

The principal objection to lamps of this type has been the difliculty in removing spent electrodes and replacing them with new ones. This diiiiculty has been due to the fact that no means was available to relieve the high pressure exerted on the electrode by the electrode feeding wheels or gears.

Release mechanisms have been devised to free the electrode, but none have thus far provided either or both manual or automatic means for efl'ecting the positive disengagement of the release and the re-engagement of the feeding means whenever the lamp is started up after a change of electrodes. A disadvantage in the present types of releases lies in the tendency for the release mechanism to become locked in the released position.

It is therefore a primary object of my invention to provide a simple and expedient means for releasing an electrode to permit ready replacement thereof, wherein said releasing means -may be positively operated to a disengaged position either manually or, preferably, automatically when the arc lamp is put into operation.

It is an additional object of my invention to provide a means for releasing the electrode which will automatically effect the re-engagement of the feeding means whenever the lamp is replaced in operation, even though the workman should inadvertently fail to return the releasing mechanism to the off position.

It is also an object of my invention to provide a release mechanism of the characterset forth in which the force tending to return said mechanism to the non-released position is at its greatest when in a position to release the electrode.

Other obiects and advantages of my invention will be apparent from a study of the following specifications read in connection with the accompanying drawings, wherein Fig. 1 is a longitudinal section illustrating the feeding and electrode releasing mechanism employed with one of the electrodes of a lamp of the type described to Richardson, No. 1936.

Fig. 2 is a transverse section taken along the line II-II of Fig. 1 and illustrating the relationship between the electrode feeding gears and the mechanism for disengaging these gears from the electrode;

Fig. 3 is a longitudinal section similar to Fig. 1 but showing the release mechanism of my invention in the released position and with certain of the feeding mechanism deleted;

Fig. 4 is a perspective view illustrating one form of the release member of my invention:

Fig. 5 is a fragmentary plan view, partly in section, taken as indicated by the line V-V of Fig.

illustrating the m the United States patent 2,060,347, issued November 10,

Fig. 6 is a longitudinal section feeding mechanism only, and showing an alternative type of release mechanism;

Fig. *1 is a transverse section taken along the line V1IVH of Fig. 6 showing additional details of the mechanism shown in Fig. 8;

Fig. 8 is a longitudinal section similar to Fig. 6 lin: illustrating a third form of release mecha- Fig. 9 is a transverse section taken along the hue IX-IX of Fig. 8;

Fig. 10 is a longitudinal section similar to Fig. 8 but illustrating an alternative arrangement of the parts shown in Fig. 8;

Fig. 11 is a longitudinal section showing a release mechanism control which may be substituted for the control shown in Figs. 1, 3 and 5;

Fig. 12 is a transverse section taken along the line XII-XII 01' Fig. 11; and

Fig. 13 is a plan view showing the control mechanism illustrated in Fig. 11.

The electrode feeding means to which the release device of my invention is applied is illustrated in Fig. 1 (it being understood that Fig. 1 illustrates only that portion of the type of arc lamp previously referred to which includes the feeding mechanism for one of the plurality of electrodes employed, the

being deleted) as including an electrode II carried in a gear housing It which encloses the driving and feeding mechanism therefor.

Power for rotating and feeding the electrode i5 is supplied through a suitable shaft II to which is aiilxed a bevel gear ll arranged to mesh with another bevel gear I! suitably attached to an electrode carrier or sleeve 20 in which the electrode i5 is inserted. The sleeve 2| is suitother electrode, mechanism associated therewith, and lamp housing m pendently of the sleeve 5 passed.

ably journaled for rotation as by means of ball bearings 2| and 22 interposed between the sleeve and the housing l6.

A spur gear 23 is suitably attached as by a key 23a to the rotatable sleeve 26 and is arranged to engage supplementary gearing (not shown), which gearing also engages another spur gear 24. The spur gear 24 is rotatably supported by the rotatable sleeve 20 so that it may rotate inde- 26 upon the exterior thereof.

The spur gear 24 has teeth 26 formed on the forward face thereof, which teeth are arranged in a spiral or scroll form. A pair ofelectrode feeding wheels 26 and 21 are provided which may be formed with gear teeth arranged to mesh with the teeth 25 of the scroll gear and to also engage the sides of the electrode 15.

In order to properly locate and support the electrode feeding wheels 26 and 21, a face plate 26 is provided which is securely attached in any suitable manner to the rotatable sleeve 20 and has provided thereon bearing brackets through which suitable shafts or axles 32 and 33 are The shafts 32 and 33 are employed as axle members for the feeding wheels 26 and 21.

Bearing brackets 30 and 3| are slotted as indicated at 34 and 36 so that the axles 32 and 33 may move inwardly and outwardly with respect to the electrode l5. Resilient means (preferably tension springs as 36 and 31) are coupled to the shafts 32 and 33 in the manner illustrated in Fig. 2 so as to urge the wheels 26 and 21 inwardly to forcibly engage the electrode I5.

In operation, the sleeve 20 is rotated by power supplied through the shaft I! in such direction gearing interposed between the spur gears 23 and 24 and the direction in which the spiral teeth 25 are developed is electrode feeding wheels 26 and 21 to rotate in opposite directions and feed the electrode l5 forwardly as indicated by arrow 33 in Fig. 1.

A heat absorber and radiator is suitably secured to the housing 16 and arranged to shield the mechanism previously described from the flame of the are so as to prevent raising the temperature of the aforementioned working parts to an undesirable value.

Although the foregoing description is directed to a common form of feeding and driving mechanism for the electrode of an arc lamp, it is included herein to facilitate the understanding of the way in which the release mechanism of my invention operates. While I have illustrated the release mechanism of my invention as being applied to the type of lamp mechanism just described, it is to be understood that this mechanism may also be readily applied to other types of electrode rotating and feeding devices.

It will be readily seen from the foregoing that in order to remove the .electrode l5 from the sleeve 26 through which it is inserted, it is necessary to disengage the and that such disengagement must be accomplished by overcoming the force of the tension springs 36 and 31 urging said wheels toward the electrode l5. It is common practice to make the springs 36 and 31' very strong in order that the electrode feeding wheels 26 and 21 may positively engage the electrode i5. In view of the strength of the springs 36 and 31 it is a difiicult task to disengage the feeding gears from the electrode unless a control means for so doing is provided.

the electrode 5 to rotate in the' so arranged as to cause the feeding wheels 26 and 21 The control means for accomplishing the above includes an internal sleeve which is interposed between the electrode [6 and the driving sleeve 20 and arranged to slide freely therebetween. The internal sleeve 45 is extended forwardly past the electrode feeding wheels 26 and 21 and terminates in a release member 46 suitably attached thereto. The sleeve 46 is provided with slots 41 and 43 (Fig. 2) through which the electrode feeding wheels 26 and 21 pass so as to engage the electrode l5.

The release member 46 is illustrated in Fig. 4 and includes a transverse portion 56 in which is provided a suitable opening 5| for attachment to the sleeve 45. Extending on either side of the electrode l5 and attached to the transverse portion 50 is a pair of longitudinal portions 52 and 53. The longitudinal portions 52' and 53 are spaced apart a sufflcient distance to straddle or pass over the bearing bracket structures 30 and I provide on each of the-longitudinal portions 52 and 53 a pair of tapered surfaces 540-54b and 54c-54d. In order that these tapered surfaces may operate as a wedging means to stretch the tension springs 36 and 31 and release the electrode feeding wheels 26 and 21 from the electrode i5, I provide suitable rollers 55a, 55b, 55c, 55d rotatably supported upon the shafts 32 and 33, rollers 55a and 55b being associated with the shaft 32 and similar rollers 55c and 55d being associated with the shaft 33.

In order that the aforementioned rollers may be held in the proper position longitudinally on the pins 32 and 33, I provide grooves 56a, 56b, 56d in the face plate 26 and extending at right angles to the shafts 32 and 33. The rollers are preferably of such diameter as to extend into the grooves associated therewith, the grooves thus operating to prevent the rollers from shifting longitudinally along the shafts 32 and 33. The rollers 55a and 55b and the complimentary rollers 55c and 55d are spaced apart by the grooves 56a, 56b, 56c, 56d the proper distance to be engaged by the tapered surfaces provided on the longitudinal members 52 and 53 of the release member 46.

Reference to Figs. 1 and 4 will show that move-- ment of the sleeve 45 to the left, as shown in Fig. 1, will cause the release member 46, attached thereto, to move to the left and force the tapered surfaces 54a-54b and 54c-54d under the rollers associated therewith in such manner as to wedge the shafts 32 and 33 outwardly from the electrode l5, thereby disengaging the feeding wheels 26 and 21 from said electrode.

In order that the sleeve 45 may be moved to the left whenever it is desired to release the electrode i5 by disengaging the feeding wheels 26 and 21, I provide thereon a collar 60 which may be suitably attached thereto as by screw threads 6i. The collar 60 may of course be adjusted longitudinally of the sleeve 45 by screwing it to the right or left along the screw threads 6|.

1 provide a lock nut 62 which may be jambed against the collar 66 in order to hold it in the desired location. The collar 60 is best shown in Fig. 5 as including an annular recess 63 formed by a pair of radial flanges 64 and 65. The collar 66 is adapted to be shifted to the right or left by a cam 66 which extends into the annular recess 63 and is arranged to engage either of the supported in a bracket member is positioned externally of the housing It and suitably secured thereto. The means for rotatably supporting the cam shaft 01 preferably comprises a suitable anti-friction roller bearing interpositioned between the cam shaft I and the bracket Cl and retained therebetween by means of a collar suitably attached to the cam shaft 61 as by means of a set screw Ila. It is to be understood that I comprehend the substitution of other types of anti-friction bearings, as for example a ball bearing, for the type of bearing shown. The cam shaft 61 terminates at its upper end in a suitable lever or handle II which may be rotated so as to move the cam I from the dotted line position as shown in Fig. 5 in a clockwise direction to the solid line position shown.

In order to limit the travel of the handle ll between the two aforementioned positions, I pro a vide stops l2 and i3 suitably attached as by with the rollers Ila,

means of screw threads 14 to the bracket 68 and so positioned that the handle Ii will rotate the cam shaft 01 through less than 180 degrees when being moved from the stop 12 to the stop 13.

I prefer to make the cam 56 in the form of an eccentric of circular cross section and of such diameter that it will substantially fill the width of the annular recess 83 so that rotation of the cam shaft 81 by means of the handle ii in 1 either direction will cause a corresponding movement of the collar ll. The relative positions assumed by the various previously described parts upon operation of the handle H to release the electrode from the electrode feeding wheels 26 and 21 is illustrated in Fig. 3.

Briefly summarizing, it will be seen that man-e ual rotation of the handle II from the position shown in Fig. ito the position shown in Fig. 3 operates to move the collar Oil and the slidable sleeve adapted thereto to the left against the force of the tension springs 30 and 31, thereby forcing the release member ll into engagement lib, etc. so as to overcome the force of the tension springs 36 and fl and disengage the electrode feeding wheels 26 and 21 from the electrode II to free said electrode therefrom and permit easy removal of the electrode {from the lamp mechanism.

' disengage the release mechanism into engagement A reverse. rotation of the handle Ii, in other words, from the position shown in Fig. 3 to the position illustrated in Fig. 1, will move the slidable sleeve in the opposite direction and disengage the release member from the feeding wheels I! and 21 so as to allow the tension springs 88 and I! to force said feeding wheels with the electrode i5.

86 on its shaft such that the electrode rotating and feeding mechanism is put into operation so as to rotate the electrode in the normal operation of the lamp (such direction being indicated by the arrow 3|) the direction in which the friction forces exerted between the flange 64 and the periphery of the cam it will be such as to tend to rotate the cam 66 and its shaft ITlna direction tending to and cause reengagement of the feeding mechanism.

I prefer to limit the movement of the cam 66 to the rangepreviously defined so that the direction of the rotation tending to be produced in the manner Prmdescribed will be limited to the counterclockwise direction as viewed in Fig. 5 so as to tend to disengage the release mechanism. In order that this tendency to cause rotation of the cam u may actually eifect a By locating the cain rotation thereof, I have provided the previously described anti-frictional force tending to rotate the cam shaft 61 will be greater than, and hence will overcome, the frictional forces in the bearing 68 tending to cause the cam shaft 61 to remain at rest.

It will therefore be observed that, should the handle ll be left in the released position as illustrated in Fig. 3, after the insertion of a new electrode II, placing the lamp mechanism in operation will impart a rotary motion to the cam shaft 61 in the manner previously described. As soon as the cam 66 has rotated from the dead center position illustrated in Figs. 3 and 5, the force tending to urge the sleeve 45 forwardly, due to the interaction of the springs 38 and 31 through the rollers and the release member 46, will cause the cam 66 to continue to rotate and allow the sleeve 45 to move to its forwardmost position, as illustrated in Fig. 1, so as to re-engage the electrode feeding mechanism with the electrode.

I have found that the provision of an antifriction type bearing for rotatably supporting the cam shaft 61 is very important, in that the automatic operation just described is not possible if an ordinary bearing is used, since the frictional forces arising therein and tending to hold the cam shaft stationary are too large to be overcome by the frictional engagement between the cam 66 and the flange 64.

The electrode release mechanism of my invention is therefore constructed in such a manner and provided with such a control mechanism that it is impossible for an operator of a lamp equipped with th s device to inadvertently operate the lamp without the feeding mechanism functioning. This is due to the fact that, as hereinbefcre described, resumption of the operation of the lamp after installation of a new electrode will automatically cause the electrode release mechanism to be disengaged from the feeding mechanism and will permit re-engagement of the feeding wheels with the electrode.

In Figs. 11, 12 and 13 I have illustrated an alternative control means for withdrawing the sleeve 45 for the purpose of releasing the electrode from the electrode feeding mechanism and which is claimed in my divisional application Serial No. 257,276, filed February 20, 1939. Rel, erence to Fig. 11 will disclose that in this form of the invention I prefer to employ a slidable sleeve 0 which extends rearwardly a sufllcient distance to extend beyond the edge of the previously mentioned bevel gear l8 to provide clearance between said gear and a collar 18 which is attached to the slidable sleeve 45a. The collar 18 may be adjustably attached to the sleeve So as by means of screw threads 19 and locked in whatever position is desired by means nut 80. The collar I8 includes a cylindrical portion Ii and a flange portion 82 of a diameter larger than the cylindrical portion II and located rearwardly with respect thereto.

A handle mechanism ator in releasing the electrode ii from the electrode feeding mechanism and a plate portion II formed integrally with the handle 84. The plate portion II is provided with a central opening ll adapted to slide over the cylindrical of the collar II and provided with three substantially equally spaced holes 81, 80 and I! of such diameter as to loosely accommodate steel balls 0, II and 82. The holes II, II and l. are

of a lock portion ll 94 which is attached to screws 95, and which provides an inwardly proright the slideable jecting rib 86. The rib 86 may be of trapezoidal cross section, providing an essentially radial surface 9] adjacent the upper steel ball 80 and a sloping surface 88 for providing strength and rigidity to the member 96.

As best illustrated in Figs. 11 and 13, the radial surface 91 is semi-helical in shape so as to provide a maximum clearance between said surface and the flange 82 at the right hand end of the flange 82 as viewed in Fig. 12 and a minimum clearance therebetween at the left hand end. The radial surface 81 cooperates with the flange 82 to confine the upper ball 90 therebetween. A suitable slot 99 is provided in the housing 94'to allow the handle 84 to extend therethrough.

It will be seen that rotation of the handle mechanism 84 to the left or counterclockwise, as viewed in Fig. 12, will cause the balls confined therein to rotate with the handle assembly. As the upper ball 90 moves between the flange 2 and the helical surface 9'1 of the projection 95 the space therebetween for said ball becomes progressively smaller so that a wedging action is developed to force the collar 18 and the sleeve 450 attached thereto to the left, as viewed in Fig. 11.

The sleeve 45a is coupled to the electrode feeding mechanism in the same manner as described relative to the sleeve 45. Hence, movement of the slidable sleeve 45a to the left will release the feeding mechanism from the electrode l in a manner identical to that previously described in connection with the sleeve 45.

Conversely, a movement of the handle 84 to the right after the sleeve 4511 has been moved to the electrode releasing position will move the upper ball 90 into that portion of the space between the flange 82 and the radial surface 91 which provides the greatest space therebetween. As previously shown, the interaction between the springs 35 and 31 and the other mechanisms forming the electrode releasing device continuously urges the slideable sleeve 45a. forwardly so that as soon as the handle 84 is moved to the sleeve 45a will move forwardly in correspondence therewith so as to place the electrode feeding mechanism into operative engagement with the electrode |5.

This form of control mechanism is also automatically releasable and is responsive to rotation of the electrode |5 to effect this release. Whenever the electrode I5 and the slideable sleeve 45a associated therewith is rotated in the direction of the arrow 38, the flange 82 of the collar II will be rotated therewith. Inasmuch as the ball 50 isconfined between the flange 82 and the helical rib 95, rotation of the flange 82 will roll the ball between said flange and said rib toward the open end of the space therebetween. This allows the sleeve 45a to slide forwardly to engage the electrode feeding wheels 26 and 21 in a manner previously described.

Other modifications of the electrode releasing mechanism include a construction which is illustrated in Figs. (i and '7 and claimed in my divisional application Serial No. 257,276. Reference to Fig. 6 reveals that in this form of the invention a modification of the release member 48 dispenses with the wedging surfaces 54a, 54b, etc. so as to provide a release member 480 upon which rollers I05, I", I" and I08 are pivotally mounted on longitudinal portions 524: and 53a by means of studs Hi8, llli, III, and III. Each of the studs is provided with an upset'head for retaining the roller associated therewith.

It will also be noted that the rollers previously described as being rotatably mounted upon the shafts l2 and 33 have been removed and in their place an. enlarged portion H3 has been substituted. It is readily seen that movement of the sliding sleeve 45 to the left through operation of either of the control mechanisms previously described will cause the rollers I05, I01, I08 and N! to engage the corresponding enlarged portions 3 of the shafts 32 and 33 in a wedging manner so as to disengage the electrode feeding wheels 28 and 21 from the electrode I5.

Figs. 8 and 9 illustrate a modification of the electrode release device of my invention in which the release member 46 is simplified so as to provide a release member 461) which includes only a transverse portion 50a. similar to the previously mentioned transverse portion 80 of member 48. In this form of my invention I prefer to employ a system of bell cranks 5 which includes bell cranks Ii. H1, H8 and H8.

The bell cranks 5 may be pivotally mounted upon suitable projections I20 formed on the hearing brackets 30 and 3| and provided with suitable holes |2| for encircling the protruding ends of the shafts 32 and 33. The lever arm portions of the bell cranks 5 are arranged to be engaged by the transverse portion 50a of the release mem ber 46?) which extends in overlapping relation relative to the bell cranks H5.

Reference to Fig. 8 will indicate that movement of the slideable sleeve 45 to the left for the purpose of releasing the electrode IE will cause those portions of the bell cranks ||5 ,which are engaged by the release member 46b to be moved to the left therewith. This movement will cause the portion of the bell cranks 5 which engage the shafts 32 and 33 to be moved outwardly away from the electrode l5, thereby effecting the previously described release. It will be noted that in this form of the invention the bell cranks are pivoted at the angle portions thereof with either end moving to effect the release of the electrode.

In Fig. I have illustrated an alternative arrangement of the bell cranks I I5 which is claimed in my divisional application Serial No. 257,276. In this modification one end of the bell crank is pivotally mounted to the bearing brackets 30 and 3| while the angle portion encircles the shafts 32 and 33 whereupon movement of the ends of the bell crank ||5 engaged with the release member 46b will cause the shafts 32 and 33 to move outwardly with respect to the electrode l5 and effect the release thereof in the manner previously set forth. In this form of the invention it should be noted that the point of engagement between the lever arm portions of the bell cranks 5 with the release member 46b lies substantially on a line between the shafts 32 and 33. Comparison of Figs. 8 and 10 reveals that this latter arrangement is more compact and less likely to interfere with the shield 40.

It will be noted that I have provided a release device in which the restoring force tending to restore the feeding mechanism to an electrode engaging position increases as the device is operated in a direction to release the electrodes. In other words. whenever the slideable sleeve 0 is moved to the left to effect the release of the electrode ll, said release is accomplished by overcoming the force of the tension springs II and II.

'l'heforce exerted by thesesprings necessarilyappears duringa release operation as a force tending to restore the slideable sleeve 4] to a nonreleased position.

Inasmuch as the mechanical advantage provided between the sleeve I and the springs 3| and I1 is of the constant ratio type, and inasmuch vas the force exerted by the springs increases as the springs are stretched during the release operation, it follows that the force tending to restore the sleeve II to the non-released position must increase as the sleeve is moved toward the released position.

. This differs from the present construction in that the mechanical advantage provided between the sleeve and the springs increases in those in present use as the sleeve is moved to a released position. This increase in mechanical advantage overcomes the increased force from the springs with the result that the restoring force on the sleeve becomes less and less as the sleeve is moved toward the released position. It will be seen, in summary, that the device'of my invention eliminates a major disadvantage in the present construction in that those in present use, in which the restoring force reduces as the feeding mechanism is released, tend to allow the feeding mechanisms to become locked in the disengaged position, thereby requiring repairs to said mechanisms and a consequent loss of time and money. 7

It will also be seen that I have provided a release mechanism for electrodes employed in an arc lamp which is provided with a control means located externally of the lamp mechanism and in which operation of said control means may be directed to either release the electrode for replacement or engage the feeding means with a new electrode.

' I claim:

1. In combination with an arc lamp having an electrode carrier rotatable about its longitudinal axis and feed wheels for feeding an electrode carried by said carrier in the direction of said axis: a means mounting said feed wheels for movement toward and away from said electrode; and control means manually operable to move said feed wheels away from said electrode and automatically operably responsive to rotation of said electrode carrier for moving said .feed wheels toward said electrode.

2. In an arc lamp, the combination of: a rotatable electrode carrier for supporting an electrode for rotation about its longitudinal axis; means for rotating said carrier; electrode feeding wheels for engaging said electrode; mounting means for mounting said feeding wheelson said carrier for movement out of engagement with said electrode and into electrode engaging P sition; a release member engageable with said mounting means for moving said feeding wheels out of engagement with said electrode; and a control means coupled to said release member and responsive to a manual operation for moving said feeding wheels out of engagement with said electrode and responsive to rotation of said electrode carrier for moving said feeding wheels to an electrode engaging position.

.ing said rollers to force '8 3. In an arc lamp. the combination of; a rotatableelectrode carrier for supporting an electrode for rotation about. its longitudinal axis; means for rotating said carrier; electrode feeding wheels for engaging said electrode; mounting means for mounting said feeding wheels on said carrier for movement out of engagement with said electrode and into electrode engaging position; a release member engageable with said mounting means for moving said feeding wheels out of engagement with said electrode; and a control means coupled to said release member and responsive to a manual operation for moving said feeding wheels out of engagement with said electrode and said electrode carrier for moving said feeding wheels to an" electrode engaging position. including a sliding sleeve interposed between said electrode and said carrier for rotation therewith and for operating said release member, a flange on said sleeve, and manually operable means engaging said flange for sliding said sleeve, said means being responsive to rotation of said flange to operate said release member to move said feeding wheels to electrode engaging position.

4. In an arc lamp, the combination of: a rotatable electrode carrier for supporting an electrode for rotation about its longitudinal axis; means for rotating said carrier; electrode feeding wheels for engaging said electrode; mounting means for mounting said feeding wheels on said carrier for movement out of engagement with said electrode and into electrode engaging position; a release member engageable with said mounting means for moving said feeding wheels out of engagement with said electrode; a sliding sleeve interposed between said electrode and said carrier for rotation therewith and for operating said release member; an'annular recess on said sleeve; and an eccentrically mounted member engaging both sides of said recess whereby rotation of said member slides said sleeve to release or engage as desired said electrode from said feeding wheels.

5. In an arc lamp having means for rotating an electrode about its longitudinal axis, the combination of: a plurality of feed wheels for engaging and feeding said electrode in the direction of said axis; shafts for rotatably supporting said feed wheels; means coupling said feed wheels to said electrode rotating means; a face plate mounting said shafts for movement toward each other to engage an electrode between said wheels and for movement away from each other to disengage said wheels from said electrode; a plurality of rollers rotatably and slideably supported by said shafts; a plurality of grooves in said face plate for engaging the sides of said rollers to prevent sliding movement thereof on said shafts; wedge means having inclined surfaces interposed between the shafts of adjacent wheels and engageable with the rollers thereon for moving said shafts away fromeach other to disengage said wheels from said electrode; and means for engaging said wedge means with said rollers.

6. In a holder for supporting an electrode, the combination of: a plurality of rotatable feeding wheels; axles mounting said feeding wheels for rotation; means mounting said axles for movement toward and awa'y from said electrode; resilient means for urging said feeding wheels into engagement with said electrode; rollers mounted on said axles; movable wedge means having inclined surfaces interposed between the rollers associated with adjacent feeding wheels for engagsaid feeding wheels out of engagement with said electrode; and means for moving said wedge means.

'7. In a holder for supporting an electrode, the combination of: a plurality of rotatable feeding wheels; axles mounting said feeding wheels for rotation; means mounting said axles for movement toward and away from said electrode; resilient means for urging said feeding wheels into engagement with said electrode; a plurality of bell cranks, each including a pivot point, an arm adjacent said pivot point engaging one of said axles, and a lever portion adjacent said arm; stationary pivot means engaging said pivot points; a movable release member engageable with each of said lever portions; and means for moving said release member into engagementwith said lever portions whereby said bell cranks rotate about said pivot points and force said feeding wheels out of engagement with said electrode.

8. In an electrode holder, the combination of; a rotatable electrode carrier; an electrode carried by said carrier; a plurality of rotatable feeding wheels; axles mounting said feeding wheels for rotation; means mounting said axles on said car-' rier for movement toward and away from said electrode; resilient means for urging said feeding wheels into engagement with said electrode; rollers mounted on said axles; movable wedge means interposed between the rollers associated with adjacent feeding wheels for engaging said rollers to force said feeding wheels out of engagement with said electrode; and a control means coupled to said movable wedge means and responsive to a manual operation for moving said feeding wheels out of engagement with said electrode carrier and responsive to rotation of said electrode carrier for moving said wedge means out of engagement with said rollers to allow said resilient means to move said feeding wheels into an electrode engaging position.

9. In an electrode holder, the combination or: a rotatable electrode carrier; an electrode carried by said carrier; a plurality of rotatable feeding wheels; axles mounting said feeding wheels for rotation; means mounting said axles on said carrier for movement toward and away from said electrode; resilient means for urging said feeding wheels into engagement with said electrode; a plurality of bell cranks, each including a pivot point, an arm adjacent said pivot point engaging one of said axles, and a lever portion adjacent said arm; stationary pivot means engaging said pivot points; a movable release member engageable with said lever portions, whereby movement of said release member rotates said bell cranks about said pivot points and forces said feeding wheels out of engagement with said electrode; and a control means for moving said release member responsive to a manual operation for moving said feeding wheels out of engagement with said electrode and responsive to rotation of said electrode carrier for moving said release member out of engagement with said lever portions to allow said resilient means to move said feeding wheels into an electrode engaging position.

10. In an arc lamp, the combination of: an electrode; a rotatable electrode carrier supporting said electrode for rotation about its longitudinal axis; electrode feeding wheels for engaging said electrode; mounting means for mounting said feeding wheels on said carrier for movement out of engagement with said electrode electrode ensll l political; a release and into member engageable, with said mounting means for moving said feeding wheels out of engagement with said electrode; a slidable member coupled to said release member and carried by said electrode carrier so as to be rotatable portion secured to said slidable member; a cam member mounted for eccentric rotation to engage said flange member; and manually operable means for rotating said cam member in a direction opposite to the direction of rotation of said flange to slide said slidable member and disengage said feeding wheels from said electrode, whereby rotation of said electrode carrier causes a reverse rotation of said cam member to move said feeding wheels into electrode engaging position.

ll. In an arc lamp, the combination of: an electrode; a rotatable electrode carrier supporting said electrode for rotation about its longitudinal axis; electrode feeding wheels for engaging said electrode; mounting means for mounting said feeding wheels on said carrier for movement out of engagement with said electrode and into electrode engaging position; a release member engageable with said mounting means for moving said feeding w eels out of engagement with said electrode; a slidable member coupled to said release member and carried. by said electrode carrier so as to be rotatable therewith; a flange portion secured to said slidable member; a cam member mounted for eccentric rotation to engage said flange member; manually operable means for rotating said cam member to move said slidable member and disengage said feeding wheels from said electrode; and means limiting the rotational movement of said cam member to a distance such that said cam memher is prevented from passing a dead-center position relative to said flange, whereby rotation of said flange will rotate said cam member in the reverse direction and move said feeding wheels to electrode engaging position.

12. In an arc lamp, the combination of: an electrode; a rotatable electrode carrier supporting said electrode for rotation about its longitudinal axis; electrode feeding wheels for en gaging said electrode; mounting means for mounting said feeding wheels on said carrier for movement out of engagement with said electrode and into electrode engagin poa tion; a release member engageable with said mounting means for moving said feeding wheels out of engagement with said electrode; a slidable member coupled to said release member and carried by said electrode carrier so as to be rotatable therewith; a flange portion secured to said slidable member; a cam member frictionally engaging said flange; means eccentrically mounting said cam member for rotation such that. the frictional resistance to said rotation is less than the frictional engagement between said cam and said flange; and manually operable means for rotating said cam member in a direction opposite to the direction of rotation of said flange to slide said slidable member and disengage said feeding wheels from said electrode, whereby rotation of said electrode carrier causes a reverse rotation of said cam member to re-engage said electrode feeding wheels with said electrode.

FIELDING C. COATES.

therewith; a flange 

